Image forming apparatus

ABSTRACT

An image forming apparatus includes an apparatus body, a door supported by the apparatus body turnably within a range of a first turning angle, a sheet stacking tray supported by the door turnably within a range of a second turning angle, and a bias member whose first end is fixed to the apparatus body and whose second end is fixed to the sheet stacking tray. The bias member pulls the sheet stacking tray to the apparatus body side by a bias force generated by the door pulling the bias member when the door is opened in the state in which the sheet stacking tray is opened and reduces a turning angle of the sheet stacking tray formed with the door to be smaller than the second turning angle at least when the door is turned by the first turning angle.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an image forming apparatus configuredto form an image on a sheet.

2. Description of the Related Art

Heretofore, there is known such an image forming apparatus including asheet feed portion provided at an under part the image forming apparatusand feeding a sheet, an image forming portion provided above the sheetfeed portion and forming an image on the sheet fed from the sheet feedportion, and a sheet discharge portion provided at an upper part of theimage forming apparatus and to which the sheet on which the image hasbeen formed is discharged. The image forming apparatus also includes aconveying path configured to move the sheet upward and a door (sidecover) permitting to expose the conveying path, when it is opened, andprovided along one side surface of an apparatus body so that a jamhandling process and maintenance works can be readily carried out.

Still further, in an image forming apparatus in which a manual feedportion configured to allow a user of the apparatus to manually feed asheet is provided on the door, a manual feed tray of the manual feedportion is turnably supported by the door and the manual feed tray isused by turning so as to be able to stack sheets when the user manuallyfeed the sheets. Due to that, if the door is opened in the state inwhich the sheets are stacked on the manual feed tray, the manual feedtray is inclined further by the turn of the door, possibly shiftingpositions of the stacked sheets on the manual feed tray and dropping thesheet from the manual feed tray. This trouble requires a user of theimage forming apparatus to correct the stacking position of the sheetson the manual feed tray in manually feeding the sheet. This work is verycumbersome for the user.

It is noted that the manual feed portion is configured such that theuser can perform the image forming operation on a sheet havingdifference size or on a different type of sheet from sheets stored in asheet feed cassette or the like of the apparatus body by setting suchsheet on the manual feed tray.

With regard this problem, Japanese Patent Application Laid-open No.2012-13828 proposes a configuration in which the body of the imageforming apparatus is linked with the manual feed tray by a flexiblestring or belt-like link member and a turning range of the manual feedtray in opening the door is restricted by the link member so as to hungthe manual feed tray.

Here, the belt-like link member described above has a substantiallyconstant length and restricts the turning range of the manual feed trayeven in a state in which the door is closed, not only in the state inwhich the door is opened. While there is such a demand that the userwants to turn the manual feed tray to an angle close to a horizontallevel in a state in which the door is closed from an aspect ofusability. However, if the turning range of the manual feed tray in thestate in which the door is closed is increased, the initial turningangle of the manual feed tray in opening the door approaches thehorizontal level. The manual feed tray tries to move in a directionapproaching the horizontal level further from the initial turning anglewhen the door is turned and opened. Accordingly, there is a problem thatit is hard to set the turning range of the manual feed tray in the statein which the door is closed to be large in order to prevent the sheetfrom dropping from the manual feed tray in the state in which the dooris opened.

SUMMARY OF THE INVENTION

According to one aspect of the present invention, an image formingapparatus of includes an apparatus body, a door supported by theapparatus body turnably within a range of a first turning angle, a sheetstacking tray supported by the door turnably within a range of a secondturning angle and stacking a sheet in a state opened with respect to thedoor, and a bias member whose first end is fixed to the apparatus bodyand whose second end is fixed to the sheet stacking tray, the biasmember pulling the sheet stacking tray to the apparatus body side by abias force generated by the door pulling the bias member when the dooris opened in the state in which the sheet stacking tray is opened andreducing a turning angle of the sheet stacking tray formed with the doorto be smaller than the second turning angle at least when the door isturned by the first turning angle.

According to another aspect of the present invention, an image formingapparatus includes an apparatus body, a door supported by the apparatusbody turnably centering on a door turning shaft, a sheet stacking traysupported by the door turnably centering on a tray turning shaft locatedabove the door turning shaft and stacking a sheet, a flexible linkmechanism whose one end is linked turnably to the apparatus body andwhose other end is linked slidably to the sheet stacking tray, a slidemechanism slidably supporting the other end of the link mechanism, and abias member linked to the other end of the link mechanism and to thesheet stacking tray, the flexible link mechanism being stretched to itsmaximum length when the door is opened in a state in which the sheetstacking tray is opened with respect to the door and the other end ofthe link mechanism being supported by the slide mechanism to be slidablein the state in which the link mechanism is stretched to its maximumlength.

Further features of the present invention will become apparent from thefollowing description of exemplary embodiments with reference to theattached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a section view schematically showing a printer according to anembodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a control portionof the printer of the embodiment.

FIG. 3 is a section view showing a state in which a door of the printershown in FIG. 1 is opened.

FIG. 4 is a section view showing a state in which a manual tray of theprinter shown in FIG. 1 is opened.

FIG. 5 is a section view showing a state in which sheets are stacked onthe manual tray of the printer.

FIG. 6 is a section view showing a state in which the door is opened byabout a half in a state in which the manual feed tray stacking thesheets is opened.

FIG. 7 is a section view showing a state in which the door is opened inthe state in which the manual feed tray stacking the sheets is opened.

DESCRIPTION OF THE EMBODIMENTS

An image forming apparatus according to an embodiment of the presentinvention will be described below with reference to FIGS. 1 through 7.The image forming apparatus according to the present embodiment of thepresent invention is provided with a manual feed tray in a door capableof exposing a conveying path such as a copier, a printer, a facsimile, amulti-function printer or the like. The image forming apparatus of thepresent invention will be described by exemplifying anelectro-photographic printer (referred to simply as a ‘printer’hereinafter) 100 forming four colors of toner images.

At first, a schematic structure of the printer 100 of the presentembodiment will be described with reference to FIGS. 1 through 3. FIG. 1is a section view schematically showing the printer 100 of the presentembodiment of the present invention, FIG. 2 is a block diagram showing aconfiguration of a control portion 50 of the printer 100 of the presentembodiment, and FIG. 3 is a section view showing a state in which a door102 of the printer 100 shown in FIG. 1 is opened.

As shown in FIG. 1, the printer 100 includes a sheet feed portion 10storing a sheet S in a sheet feed cassette or the like and feeding thesheet S from the sheet feed cassette and a manual feed portion 20enabling to manually feed a sheet S. The printer 100 also includes animage forming portion 30 configured to form an image on the sheet S fedfrom the sheet feed portion 10, a discharge roller pair 40 dischargingthe sheet S out of the apparatus, and a control portion 50 controllingthese portions.

The sheet feed portion 10 is provided at a lower part of the printer 100and includes a fed sheet stacking portion (sheet feed cassette) 11 and asheet feed roller pair (sheet feed member) 12 feeding the sheet Sstacked in the fed sheet stacking portion 11. It is noted that a pickupportion picking up the sheet S out of the fed sheet stacking portion 11is not shown in FIG. 1. The manual feed portion 20 is provided on oneside portion (right-hand side in FIG. 1) of the printer 100. It is notedthat the manual feed portion 20 will be described in detail later.

The image forming portion 30 is provided above the sheet feed portion 10and includes photoconductive drums 31 a through 31 d on which tonerimages of yellow, magenta, cyan and black colors are formed and anexposure unit 32 irradiating a laser beam to the photoconductive drums31 a through 31 d. The image forming portion 30 also includes a transferportion 33 transferring the toner images on the sheet S, and a fixingportion 34 fixing the toner images transferred to the sheet S. Thedischarge roller pair 40 is provided at an upper part of the printer 100(above the image forming portion 30).

As shown in FIG. 2, the control portion 50 includes a CPU 51 driving andcontrolling the sheet feed portion 10 and others and a memory 52 storingvarious programs, various information and others.

As shown in FIG. 3, the printer 100 also includes a body 101 of theprinter (referred to simply as a ‘printer body’ or an ‘apparatus body’hereinafter) and a side cover (referred to simply as a ‘door’hereinafter) 102 capable of exposing an inside (a conveying pathconveying and guiding a sheet) of the printer body 101. The sheet feedportion 10, the image forming portion 30 and others are disposed withinthe printer body 101. The manual feed portion 20 is disposed within thedoor 102. The door 102 is provided on one side (on the right-hand sidein FIG. 3) of the printer body 101 and is supported by the printer body101 turnably centering on a door turning shaft 103 provided at a lowerpart of the printer body 101. It is noted that an opening angle a (firstturning angle) of the door 102 formed between the door 102 and theprinter body 101 is restricted by a door turning angle restrictingportion (first turn restricting portion) 102A composed of a four jointlink constructed by using an arm member 102A1 whose one end is turnablyattached to the printer body 101 and whose other end is slidablyattached to the door 102 to a range enabling a user to carry out a jamhanding process, and a maximum opening angle a of the door 102 is set atabout 40° in the present embodiment.

The door 102 also opens (exposes) a part of the conveying path 104conveying the sheet S when it is opened and composes a part of theconveying path 104 when it is closed (see FIG. 1). It is noted that theconveying path 104 composed a so-called vertical path extending from thesheet feed portion 10 upward toward the discharge roller pair 40 whilepassing through a transfer nip N of the transfer portion 33 and thefixing portion 34. The door 102 is provided with a duplex conveying path107 and a 110 described later.

Next, an image forming operation of the printer 100 (image formingcontrol made by the control portion 50) will be briefly described basedon the components described above. In response to a start of the imageforming operation, the exposure unit 32 irradiates the laser beam onsurfaces of the photoconductive drums 31 a through 31d corresponding toan image information signal transmitted from a personal computer or adocument reading portion not shown. Thereby, the surfaces of thephotoconductive drums 31 a through 31 d charged with predeterminedpolarity and potential are exposed and electrostatic latent images areformed. When the electrostatic latent images are formed on the surfaceof the photoconductive drums 31 a through 31 d, a developing portion notshown develops the electrostatic latent images and visualizes as tonerimages. The visualized respective toner images are superimposed andtransferred to an intermediate transfer belt and are conveyed to thetransfer nip N of the transfer portion 33 by the intermediate transferbelt.

In parallel with the toner image forming operation described above, thesheet feed roller pair 12 feeds the sheets S stacked in the fed sheetstacking portion 11 to the conveying path 104 while separating one byone. It is noted that in a case of manual feed, the manual feed portion20 feeds the sheet S toward the conveying path 104. Then, when the sheetS is fed to the conveying path 104, a registration roller pair 105conveys the sheet S to the transfer nip N with timing synchronized withthe toner image on the intermediate transfer belt and the transferportion 33 transfers the toner image on the sheet S. After that, thefixing unit 34 fixes the toner image by heat and pressure and thedischarge roller pair 40 discharges the sheet S out of the apparatus.The sheet S discharged out of the apparatus is stacked on a dischargedsheet stacking portion (discharge tray) 106 provided at an upper part ofthe printer 100.

It is noted that in a case where images are formed on both surfaces(first and second surfaces) of the sheet S, the discharge roller pair 40is rotated reversely before the sheet S is discharged out of theapparatus to convey the sheet S to a duplex conveying path 107. Then,duplex conveying roller pairs 108 and 109 feed the sheet S through theduplex conveying path 107 again to the conveying path 104 and the imageforming portion 30 forms an image on the second surface of the reversedsheet S. An operation thereafter is the same with what described above,so that an explanation thereof will be omitted here.

Next, the manual feed portion 20 described above will be described withreference to FIGS. 4 through 7. At first, a configuration of the manualfeed portion 20 will be described with reference to FIG. 4. FIG. 4 is asection view showing a state in which a manual feed tray 21 of theprinter 100 shown in FIG. 1 is opened.

As shown in FIG. 4, the manual feed portion 20 includes the manual feedtray 21 on which the sheet S is stacked and a manual feed roller pair(manual feed member) 22 feeding the sheet S stacked on the manual feedtray 21. The manual feed portion 20 also includes a link unit (linkmechanism) 23 linking the manual feed tray 21 with the printer body 101and restricting a turning angle of the manual feed tray 21 formed withthe printer body 101 such that the turning angle becomes less than apredetermined turning angle.

The manual feed tray 21 is provided on one side (right-hand side in FIG.4) of the door 102 and is supported by the door 102 turnably centeringon a tray turning shaft (turning shaft portion) 21 a provided at a lowerpart of the one side surface of the door 102 and above the door turningshaft 103 of the door 102. The manual feed tray 21 is also constructedsuch that it can be stored within the door 102 so as not to project outof a case surface of the door 102 when the manual feed tray 21 is closed(see FIG. 1). It is noted that an opening angle β (second turning angle)of the manual tray 21 formed between the door 102 in the closed stateand the manual tray 21 is restricted by a tray turning angle restrictingportion (second turn restricting portion) 20A composed of a four jointlink constructed by using an arm member 201A1 whose one end is turnablyattached to the door 102 and whose other end is slidably attached to themaximum opening angle β of the manual tray 21=about 70° in the presentembodiment.

The manual feed roller pair 22 is provided along a manual feed path 110connecting the conveying path 104 with the manual feed portion 20 andconveys the sheet S stacked on the manual feed tray 21 to the conveyingpath 104 through the manual feed path 110. It is noted that a pickupportion picking up the sheet S stacked on the manual feed tray 21 is notshown in FIG. 4.

The link unit 23 includes a flexible (bendable) link portion 24 and abias portion 25 biasable so as to be able to raise the manual feed tray21 to the printer body 101 side (apparatus body side). The link portion24 of the present embodiment is a link mechanism composed of a firstlink member 24 a whose one end is turnably supported by the printer body101 and a second link member 24 b linked to another end of the firstlink member 24 a. The bias portion 25 is composed of a bias spring (biasmember) 26 connected to another end of the second link member 24 b and aslide mechanism 27 sliding the other end of the second link member 24 bsubstantially in parallel with a stacking surface 21 c of the manualfeed tray 21. The bias spring 26 is a coil spring.

One end of the first link member 24 a is supported by the printer body101 turnably above the tray turning shaft 21 a of the manual feed tray21. Another end of the first link member 24 a is linked flexibly withone end of the second link member 24 b by a link shaft 28. One end(first end) of the bias spring 26 is connected to the other end of thesecond link member 24 b and another end the bias spring 26 is connectedto an end portion 21 b of the manual feed tray 21. Then, the bias spring26 biases the second link member 24 b so as to pull toward the endportion 21 b side of the manual feed tray 21. Accordingly, the linkportion 24 composed of the first and second link members 24 a and 24 bis configured such that the link portion 24 can bend or extend as thedoor 102 and the manual feed tray 21 are opened/closed.

As described above, the first end of the bias spring 26 is fixed to theprinter body 101 through the link portion 24 and the second end thereofis fixed to the manual feed tray 21 such that the bias spring 26 pullsup the manual feed tray 21 when the door 102 is opened as describedlater in detail. That is, the bias spring 26 pulls the manual feed tray21 to the printer body side by a bias force generated when the door 102is opened in the state in which the manual feed tray 21 is opened andreduces the turning angle of the manual feed tray 21 formed with thedoor 102 to a turning angle small than the second turning angle β atleast when the door 102 is opened to the first turning angle α.Therefore, the stronger the bias force of the bias spring 26, the morethe position of the manual feed tray 21 tends to be stabilized. However,if the bias force is too strong, there is a possibility that the manualfeed tray 21 jumps up in linkage with the operation of opening the door102. Then, the bias force of the bias spring 26 is set such that theposition of the manual feed tray 21 can be maintained in a state inwhich the sheets S are fully loaded on the manual feed tray 21. Forinstance, a force around 30 N will suffice as a force necessary forpulling up a total weight of a weight of the manual feed tray 21 and amaximum loading weight of the sheets S and the bias force of the biasspring 26 is set at 30 N in the present embodiment.

The slide mechanism 27 includes a projection 27 a provided at the otherend of the second link member 24 b and a slide member 27 b through whicha 27 c sliding the projection 27 a (the other end of the second linkmember 24 b) substantially in parallel with the manual feed tray 21 c ofthe manual feed tray 21. While the slide member 27 b is attached to themanual feed tray 21, the slide member 27 b may be formed integrally withthe manual feed tray 21.

Next, an operation (action) of the manual feed tray 21 when the door 102is opened in the state in which the manual feed tray 21 is opened willbe explained with reference to FIGS. 5 through 7 in addition to FIG. 1.FIG. 5 is a schematic section view of the apparatus showing a state inwhich the sheets S are stacked on the manual feed tray 21 of the printer100, FIG. 6 is a schematic section view of the apparatus showing a statein which the door 102 is opened by about a half in the state in whichthe manual feed tray 21 stacking the sheets S is opened, and FIG. 7 is aschematic section view of the apparatus showing a state in which thedoor 102 is opened in the state in which the manual feed tray 21stacking the sheets S is opened.

As shown in FIG. 1, the first and second link members 24a and 24 b bendat the link shaft 28 in a state in which the manual feed tray 21 isstored in the door 102 and are configured so as not to interfere thestorage of the manual feed tray 21 at a position close to each other.The bias spring 26 is contracted and the projection 27 a (the other endof the second link member 24 b) is located at a front edge side of theslide groove 27 c.

When the manual feed tray 21 is pulled out from this state, the secondlink member 24 b turns centering on the link shaft 28 in linkage withthe turn of the manual feed tray 21 and stops the turn of the manualfeed tray 21 as the end on the manual tray 21 side of the arm member20A1 of the tray turning angle restricting portion 20A slides to asliding limit position on the door side as shown in FIG. 5. The biasspring 26 is contracted also at this time and the projection 27 a (theother end of the second link member 24 b) is located at the front edgeof the slide groove 27 c. The link portion 24 is kept in the bendedstate because the door turning shaft 103 of the door 102 and the trayturning shaft 21 a of the manual feed tray 21 are located at the sameposition in terms of a horizontal direction (horizontal direction inFIG. 4) of the printer body 101. That is, a turning range of the manualfeed tray 21 is not restricted by the link unit 23 and the link unit 23does not interfere the turn of the manual feed tray 21 when the manualfeed tray 21 is just opened/closed.

In this state, the first and second link members 24 a and 24 b bend andthe link shaft 28 is located near the manual feed tray 21 c of themanual feed tray 21. In other words, the first link member 24 a islocated along the printer body 101 and the second link member 24 b islocated along the manual feed tray 21. Therefore, the first and secondlink members 24 a and 24 b do not interfere the user in stacking thesheets S on the manual feed tray 21.

When the door 102 is turned in an opening direction from this state, thefirst and second link members 24 a and 24 b are stretched as the manualfeed tray 21 separates from the printer body 101. It is because the trayturning shaft 21 a of the manual feed tray 21 gradually separates in theright-hand side of the printer body 101 (the right-hand side in FIG. 4)with respect to the door turning shaft 103 of the door 102. Thereby, thebended first and second link members 24 a and 24 b are graduallysubstantially straightened, i.e., extended to a maximum length, duringwhen the door 102 is opened to its maximum opening angle. When the door102 is turned further from the state in which the first and second linkmembers 24 a and 24 b are substantially straightened, the other end ofthe second link member 24 b (the projection 27 a) moves to the trayturning shaft 21 a side along the slide groove 27 c by going against thebias force of the bias spring 26 and pulls the bias spring 26.

When the door 102 is opened by about a half (α/2) as shown in FIG. 6,the manual feed tray 21 turns along with the downward move of the door102 in the state in which the manual feed tray 21 is restricted at acertain angle (70°) by the tray turning angle restricting portion 20A.At this time, the first and second link members 24 a and 24 b arestretched from the bending state and the link unit 23 is stretched toits maximum length. Until when the link unit is stretched to its maximumlength, the tray turning angle restricting portion 20A provided in theopening door 102 restricts an inclination of the manual feed tray 21because the first and second link members 24 a and 24 b are configuredso as not to interfere the opening operation of the manual feed tray 21.Due to that, a relative angle between the manual feed tray 21 and afloor surface is reduced by opening the door 102. While this relativeangle depends also on the relationship between the first and second linkmembers 24 a and 24 b and others, the relative angle of the manual feedtray 21 formed with the floor surface changes within a range of 20 to 5°in the present embodiment.

It is noted that while the length of the link unit 23 is maximized whenthe door 102 is opened by about a half as shown in FIG. 6 in the presentembodiment, the opening angle of the door 102 when the link unit 23 isstretched to its maximum length is not limited to that. The openingangle of the door 102 when the link unit 23 is stretched to its maximumlength may be set at any angle as long as it is less than an angle whenthe door 102 is opened in maximum.

As shown in FIG. 7, when the door 102 is turned further, the other endof the second link member 24 b (the projection 27 a) moves to a base end(the tray turning shaft 21 a side) of the slide groove 27 c as the linkunit 23 has already stretched to its maximum length. The bias spring 26is stretched by this move of the projection 27 a of the second linkmember 24 b.

When the bias spring 26 is stretched to its maximum length, i.e., whenthe link unit 23 is stretched to its maximum length, a force acts on themanual feed tray 21 in a direction of raising the manual feed tray 21 tothe door 102 side centering on the tray turning shaft 21 a by a biasforce (resilient force) of the bias spring 26. Thereby, the manual feedtray 21 rises vigorously so as to approach the door 102 more than theprevious state (the state in FIG. 7). When the manual feed tray 21rises, the sheets S stacked on the manual feed tray 21 move to themanual feed roller pair 22 side even if they are shifted.

As described above, according to the printer 100 of the presentembodiment, because the bias spring 26 is provided in the link unit 23,the manual feed tray 21 can be raised suitably before the door 102 isopened to the end. Due to that, the sheets S on the manual feed tray 21will not drop when the door 102 is opened and the sheets S can be alsoreturned to a feed position even if the stacked position of the sheets Sis shifted from the feed position. Thereby, it is possible to prevent afeed jam otherwise caused by the shift of the feed position of thesheets S.

Still further, it is possible to buffer a shock otherwise acting on themanual feed tray 21 when the user vigorously opens the door 102 byproviding the bias spring 26 in the link unit 23. Therefore, it ispossible to reliably prevent the sheet S on the manual feed tray 21 fromdropping and to reduce the occurrence of the shift of the position ofthe sheet S.

It is also possible to smooth the operation carried out in switching themoving direction of the manual feed tray 21 (the operation of the manualfeed tray in turning up from the state shown in FIG. 7 in the presentembodiment) by providing the bias spring 26 in the link unit 23.Accordingly, it is possible to reduce unnecessary sounds and shocks frombeing generated.

The printer 100 of the present embodiment uses the first and second linkmembers 24 a and 24 b as the link portion 24 and the slide member 27 b.Therefore, the first and second link members 24 a and 24 b will notinterfere the user in stacking the sheets S on the manual feed tray 21for example.

The printer 100 of the present embodiment is configured such that theother end of the second link member 24 b (the other end of the set oflinks) is slidable and is biased in one direction. Therefore, the linkscan flexibly react without being strictly limited in terms of the lengthof the links, positions of centers of turn of the respective members andothers. That is, the links makes it possible to flexibly deal withrestrictions on design and precision of parts.

As described above, the printer 100 of the present embodiment suitablyrestricts the turning angle of the manual feed tray 21 regardless theopening/closing operation of the door 102 and can prevent the fall andthe shift of the position of the sheets S stacked on the manual feedtray 21.

While the present embodiment of the present invention has beenexplained, the present invention is not limited to the presentembodiment described above. Still further, the advantageous effectsdescribed in the present embodiment of the present invention are merelyan enumeration of the most suitable effects brought about from thepresent invention, and the effects of the present invention are notlimited to what described in the present embodiment of the presentinvention.

For instance, while the present embodiment has been explained by usingthe manual feed portion 20 as a sheet stacking portion, the presentinvention is not limited to that. When a discharged sheet stacking tray(sheet stacking tray) stacking the sheet S on which an image has beenformed and has been discharged out of the apparatus is provided on adoor capable of exposing an inside of the apparatus body, the sheetstacking portion described above is applicable to a discharge sheetstacking portion having a discharge sheet stacking tray.

Still further, while the present embodiment has been described by usingthe first and second link members 24 a and 24 b as the link portion 24,the present invention is not limited to that. For instance a member,e.g., a sheet-like or string-like member, formed of a flexible materialsuch as bendable synthetic resin (polypropylene or the like) and rubbermay be used as the link portion. It is possible to obtain the similareffects even if such member is used.

While the present embodiment has been also explained by using the biasspring 26 and the slide mechanism 27 as the bias portion 25, the presentinvention is not limited to such configuration. The bias portion may becomposed of only the bias spring (bias member).

While the present embodiment has been also explained by using the biasspring 26 as the bias member 25, the present invention is not limited tothat. The bias member may be constructed by using a hydraulic damper, apneumatic damper or an elastic member. Still further, while the doorturning angle restricting portion 102A and the tray turning anglerestricting portion 20A are constructed by the four joint link in theembodiment described above, the door and tray turning angle restrictingportions may be configured such that the end on the apparatus body sideof the arm member 102A and the end on the door side of the arm member20A slide for example. The turning angle restricting portions may bealso constructed by any link structure other than the four joint link.The door and tray turning angle restricting portions 102A and 20A may becomposed of any mechanism other than the link mechanism, such as astring-like member such as a wire of a predetermined length, aconfiguration in which a projection is fitted into a long hole, and amechanism restricting a turning range of the door turning shaft 103 andthe tray turning shaft 21 a by using gears and stoppers.

The present embodiment has been also explained by using theelectro-photographic image forming process as the image forming portionforming an image on the sheet S, the present invention is not limited tosuch configuration. For instance, the image forming portion forming theimage on the sheet S may be what uses an ink jet image forming processforming an image on the sheet S by discharging liquid ink from a nozzle.

While the present invention has been described with reference to theexemplary embodiments, it is to be understood that the invention is notlimited to the disclosed exemplary embodiments. The scope of thefollowing claims is to be accorded the broadest interpretation so as toencompass all such modifications and equivalent structures andfunctions.

This application claims the benefit of Japanese Patent Application No.2013-137015, filed on Jun. 28, 2013, and Japanese Patent Application No.2014-115637, filed on Jun. 4, 2014 which are hereby incorporated byreference herein in their entirety.

What is claimed is:
 1. An image forming apparatus comprising: anapparatus body; a door supported by the apparatus body turnably within arange of a first turning angle; a sheet stacking tray supported by thedoor turnably within a range of a second turning angle and stacking asheet in a state opened with respect to the door; and a bias memberwhose first end is fixed to the apparatus body and whose second end isfixed to the sheet stacking tray, the bias member pulling the sheetstacking tray to the apparatus body side by a bias force generated bythe door pulling the bias member when the door is opened in the state inwhich the sheet stacking tray is opened and reducing a turning angle ofthe sheet stacking tray formed with the door to be smaller than thesecond turning angle at least when the door is turned by the firstturning angle.
 2. The image forming apparatus according to claim 1,further comprising a link mechanism including a first link attached tothe apparatus body and a second link attached to the first end of thebias member, the link mechanism linking the apparatus body with thesheet stacking tray through the bias member and being flexible andstretchable as the door and the sheet stacking tray are opened/closed.3. The image forming apparatus according to claim 2, wherein the linkmechanism is stretched to its maximum length during when the door in thestate in which the sheet stacking tray is opened turns up to the firstturning angle.
 4. The image forming apparatus according to claim 3,further comprising a slide mechanism configured to move an end of thesecond link on a side linked with the bias member along a stackingsurface of the sheet stacking tray.
 5. The image forming apparatusaccording to claim 4, wherein the bias member is pulled by the end ofthe second link in a state in which the link mechanism is stretched toits maximum length and the end of the second link is slid along theslide mechanism in response to an opening operation of the door.
 6. Theimage forming apparatus according to claim 5, wherein the bias memberincludes a bias spring.
 7. The image forming apparatus according toclaim 6, further comprising a manual feed portion provided on one sidesurface of the apparatus body and capable of feeding a sheet into theapparatus body; wherein the sheet stacking tray is a manual feed trayprovided in the manual feed portion and stacking sheets to be fed intothe apparatus body.
 8. The image forming apparatus according to claim 7,further comprising a conveying path guiding the sheet being conveyedwithin the apparatus body; wherein the conveying path is exposed byopening the door.
 9. The image forming apparatus according to claim 1,further comprising a first turn restricting portion restricting aturning range of the door within the first turning angle; and a secondturn restricting portion restricting a turning range of the sheetstacking tray to the second turning angle.
 10. An image formingapparatus comprising: an apparatus body; a door supported by theapparatus body turnably centering on a door turning shaft; a sheetstacking tray supported by the door turnably centering on a tray turningshaft located above the door turning shaft and stacking a sheet; aflexible link mechanism whose one end is linked turnably to theapparatus body and whose other end is linked slidably to the sheetstacking tray; a slide mechanism slidably supporting the other end ofthe link mechanism; and a bias member linked to the other end of thelink mechanism and to the sheet stacking tray; the flexible linkmechanism being stretched to its maximum length when the door is openedin a state in which the sheet stacking tray is opened with respect tothe door and the other end of the link mechanism being supported by theslide mechanism to be slidable in the state in which the link mechanismis stretched to its maximum length.